Analyzing data gathered in a 10-nation study of psychoses by the World Health Organization (WHO), Susser and Wanderling1 found that the incidence of nonaffective psychoses with acute onset and full recovery was about 10 times higher in premodern cultures than in modern cultures. Transient psychoses with full recovery were comparatively rare in modern cultures. Such a dramatic difference begs for explanation.

The WHO studies of psychoses worldwide have made it clear that those with psychoses in general have a better course and outcome in premodern cultures.2-4 Some theorists have speculated that the better course and outcome are due to lesser demands made on patients in the agrarian economies of underdeveloped nations. However, further investigations in Japan, Hong Kong, and Singapore—all societies of advanced economic development--have also demonstrated a better course and outcome for psychoses than in Western cultures.5-8

Hopper and Wanderling9 analyzed the data from the WHO studies, as well as 2 additional samples (from Hong Kong and Madras/Chennai, India), for sources of bias that could account for a differential advantage in course and outcome for persons living in developing countries. They considered several factors: differences in follow-up, arbitrary grouping of research centers, diagnostic ambiguities, selective outcome measures, sex, and age. None of these potential confounders explained the observed differences. They concluded that local cultural practices were probably implicated in this long-standing and provocative finding of a differential advantage in course and outcome in premodern cultures.

Effects of culture
Transient psychoses with full recovery are much more common in premodern cultures that accept the reality of spirits. In premodern cultures, psychoses are usually characterized by paranoid delusions of attack by sorcery, witchcraft, or demonic beings—with accompanying auditory and visual hallucinations.5,10-14 These cultural beliefs structure not only the symptoms of illness but also the indigenous diagnoses, treatments, and outcomes.11,12

Traditional treatment in a premodern society usually consists of a prescribed period of rest; sympathy; heightened social support; alleviation of underlying social stresses; exploration of alternative coping strategies; and various types of traditional healing rituals, sometimes lasting days or weeks, and frequently resulting in the full recovery of the patient.5,11-18

Dutch psychiatrist Marjolein van Duijl,14 who was head of the department of psychiatry at a hospital in southwest Uganda for 6 years, conducted a study there of 120 patients experiencing "spirit possession." Forty-one percent of these patients reported hearing voices, and 65% spoke in a voice different from their own. Of these 120 patients, 45% felt better, and 54% experienced complete recovery after treatment by traditional healers.

Cultural psychiatrists Wolfgang Jilek5 and Beng-Yeong Ng13 concluded that the factor determining course and outcome is not the difference between high and low economic development, but the difference between modern and premodern cultures that have preserved traditional elements in their world views and healing practices. Jilek further suggested that an acute psychotic episode evoked by traumatizing experiences and severe social stress would be of short duration if the society responded with sympathy, social support, and traditional healing practices. However, if there is rejection and social isolation, the traditional extended kinship network is no longer in operation; if there is an expectation of a chronic illness when a patient shows an acute psychotic reaction, transient psychoses could evolve into chronic psychoses, particularly if modernization has become pervasive.